基于GPM卫星探测的夏季高原涡降水结构特征

Characteristics of Precipitation Structure of Tibetan Plateau Vortex in Summer Detected by GPM Satellite

利用GPM卫星的双频反演产品DPR_MS和ERA5再分析数据,对2016~2020年夏季青藏高原上空能被GPM卫星探测到的32例高原涡降水特征进行研究。结果表明:(1)高原涡在高原上降水强度偏小,绝大部分低于2 mm/h,雨顶高度主要在6~9 km。降水类型以深厚弱对流为主(占59.64%),其次是浅薄降水(占40.35%),深厚强对流极少。(2)高原西部降水涡绝大多数为深厚弱对流、平均雨顶高度明显高于东部涡,但东、西部涡的平均降水强度没有明显差异。浅薄降水频次呈“东高西低、北高南低”的空间分布特征,深厚弱对流降水则相反。(3)深厚弱对流降水受高原涡强上升运动影响显著,在6.5~7.5 km高度有大量有效半径为1.1 mm的雨滴粒子堆积,近地面较强降水(7 mm/h)的雨滴破碎过程明显。浅薄降水的反射率因子在各个高度持续增大,其地面降水主要由雨滴粒子碰并形成,地表雨强受雨滴浓度影响明显。

Based on the dual-frequency products DPR_MS of GPM satellite and ERA5 reanalysis data,the precipitation characteristics of 32 Tibetan Plateau vortices(TPVs)detected by GPM satellite over the Tibetan Plateau in the summer of 2016~2020 were studied.The results show that:(1)The precipitation intensity of the TPVs on the plateau was relatively low,most of which were less than 2mm/h.The type of TPV precipitation was mainly deep weak convection,accounting for 59.64%;the second was shallow precipitation,accounting for 40.35%;the deep strong convection was rare.(2)Most of the precipitation TPVs in the western part of the TP were in the form of the weak deep convection,and the average rain top was significantly higher than that of the eastern TPVs,while there was no significant difference in the average precipitation intensity between the eastern and western TPVs.The frequency of shallow precipitation was higher in the east and north than that in the west and south,while the characteristics of the frequency of deep weak convective precipitation was the opposite.(3)In vertical direction,the deep weak convective precipitation was significantly affected by the strong upward movement of TPVs.A large number of raindrop particles with an effective radius of 1.1mm accumulated in the deep weak convective precipitation at the height of 6.5~7.5 km,and the raindrop breaking process of the strong precipitation(>7 mm/h)near the ground was obvious.The reflectiv-ity factor of the shallow precipitation increased continuously at each height,and the surface precipitation was mainly formed by raindrop collision,and the surface rain intensity was obviously affected by raindrop concentration.